HUSSEINIA, Iraq -- For Capt. Todd Mitchell, the difference between
living and dying is measured in minutes.

A National Guardsman from Wichita
Falls, Texas, Mitchell was trailing behind a U.S. military convoy last week when
a bomb planted by the roadside suddenly exploded near one of the vehicles.

One soldier was killed and three others were seriously injured.

"It
hits you especially hard when you know it could have been you," said Mitchell,
an automobile insurance salesman. "It can be extremely scary at times. Any
time you leave [the base] and return alive, it's a successful mission."

Four
months after President Bush declared an end to major combat operations in Iraq,
nearly 150,000 U.S. troops deployed in the country are facing a nerve-racking
guerrilla war where the enemy is hidden and danger is everywhere.

The unpredictable
dangers are only adding to the stresses of the Iraq deployment, which the Congressional
Budget Office reported this week is stretching active-duty U.S. forces so thinly
that they cannot be maintained at current levels beyond next spring.

That
means Washington could hope to sustain the occupation only by activating more
National Guard and Reserve units, or persuading other nations to contribute significantly
more troops under a new United Nations resolution the Bush administration is now
proposing.

Yet the list of perils confronting troops in Iraq is growing
so long that some foreign governments are expressing reluctance to commit any
soldiers.

Roadside explosives are placed beneath dead dogs, in cardboard
boxes and, in one recent attack, under a case of Pepsi-Cola. Suicide bombers attack
while riding bicycles, and passing motorists in pickup trucks stage drive-by shootings.
Mortar rounds are lobbed into U.S. bases.

A bomb was even floated down a
river on a makeshift pontoon, destroying a civilian bridge built by U.S. forces.

"It
was terrifying," said Spec. Leigh Ann Dunn, a National Guard member from
Pierre, S.D., who was guarding the bridge. "We had been mortared and taken
small arms fire, but we had never been attacked like that."

While U.S.
military commanders give the insurgents little credit for tactics and organization,
they recognize the danger the guerrilla attacks present to their troops.

Lt.
Col. Michael Mahoney, commander of Task Force Thunder, a 485-member force comprised
of the 3rd Battalion, 16th Field Artillery Regiment and other units, said he repeatedly
reminds his troops to be alert.

"They are very safe in here,"
said Mahoney, speaking from his command post at a former Iraqi military hospital
12 miles north of Baghdad. "When they leave, it's full battle rattle and
game on, and they know it. When they go out of the gate, it's very, very serious."

At
least 68 U.S. soldiers have been killed in Iraq since May 1. But numerous others
have narrowly escaped injury or received minor wounds and returned to duty.

Luck
often plays a role in survival.

One U.S. soldier described how a rocket-propelled
grenade skipped harmlessly off the hood of his vehicle. Others talk about bullets
narrowly "zinging" past their heads.

Sgt. Shayne Thomas, a Texas
National Guardsman assigned to Task Force Thunder, was riding in a convoy in June
when an attacker lobbed a grenade into his Humvee.

The grenade exploded
and sent shrapnel tearing into Thomas' legs, but he received only minor injuries
because the explosive misfired.

"If it had fused right, three of us
would have been gone," said Thomas, who is with the Delta Battery 2-20 Field
Artillery.

Thomas, a correctional officer and a veteran of the Persian Gulf
war, said the current conflict is far more difficult for U.S. troops than the
1991 war because this time it's hard to identify the enemy.

The insurgents
don't wear uniforms, and they fire at U.S. troops from rooftops, outdoor markets
or other heavily populated areas.

Gunmen shoot, abandon arms

The attackers
frequently drop their weapons and flee rather than directly engage U.S. forces.
Rocket-propelled grenades are sometimes fired by insurgents on motorcycles who
scurry down alleys and narrow streets to evade pursuing U.S. tanks and Humvees.

At
best, U.S. soldiers see a muzzle flash from a rifle or movement from behind bushes
or a desert berm. U.S. troops say they "pick a spot and start lighting it
up" with gunfire but often find nothing when the shooting stops.

"In
the gulf war we fought in the open," Thomas said. "Here you don't see
them. They melt back into the surroundings."

Many soldiers say they
have learned to trust no one. Each day is unpredictable. Troops on patrol may
encounter groups of smiling children giving them the thumbs-up sign; they could
also find themselves pelted with rocks and bottles, or, worse, under fire.

The
uncertainty forces troops to make split-second decisions with potentially lethal
consequences.

Is the roadside vendor standing close to a U.S. convoy selling
fruit, or is he rigging a bomb? Is the nearby gunfire directed at U.S. forces
or, as is the tradition here, is it merely shots fired during a wedding celebration?

When
an Iraqi recently ran a checkpoint and almost hit two soldiers, U.S. troops attached
to Task Force Thunder said they fired warning shots and then opened fire on the
vehicle. The driver, who was killed, turned out to be an unarmed civilian. But
U.S. soldiers said they feared he could have been a suicide bomber.

"We
don't know if he saw the checkpoint and panicked," explained Sgt. Tony Yates,
a Chicago native with the 2nd Brigade Reconnaissance Troop. "It would have
been really bad if he had weapons or explosives and injured one of our soldiers."

That
everyone in Iraq seems to be armed adds to the difficulty of determining who is
an insurgent.

Weapons ubiquitous

U.S. troops say owning an assault
rifle is a rite of passage for Iraqis. The countryside is littered with unexploded
shells, rockets and other ordnance.

Mahoney, who called Iraq "the most
heavily armed country in the world," said that only 2 miles from the base
there are 10,000 tank rounds and 5,000 surface-to-surface rockets in an open field.

Sgt.
Jason Campbell, a member of Alpha Company 1-67 Armor Battalion, described with
shock how he discovered 3,000 grenades hidden in a giant haystack.

"We
went out on so many different raids and it was a dry hole," said Campbell,
who is from Calico Rock, Ark. "Then, we went out in the heat of the day and
the next thing you know there are all these grenades. It is like looking for a
needle in a haystack."

The evolving role of U.S. troops in Iraq has
added to the burden of the war.

Instead of planning for set-piece battles,
U.S. commanders in Iraq spend much of their time meeting local sheiks, organizing
city council elections and figuring out how to provide reliable electricity and
water service to residents.

For the average soldier, the war in Iraq often
means going out on patrols in gritty urban neighborhoods, scrambling to capture
individual gunmen as tracer bullets light up the night sky, or manning nighttime
roadblocks to capture insurgents and weapons.

"It's frustrating,"
explained Lt. Rob Cathey, a platoon leader from Winston-Salem, N.C., who was manning
a late night roadblock last week near Husseinia. "It's going to take a long
time. But that guy with the gun today could be shooting at us tomorrow."

The
primary danger to U.S. forces comes from artillery shells, mortar rounds and other
devices hidden along roadsides and detonated by remote control. Soldiers in Task
Force Thunder suffered three separate roadside attacks in recent weeks, though
none caused major casualties.

Humvee drivers and others say they have memorized
every bump and pothole along frequently traveled highways. Soldiers scan the roadside
looking for men using satellite telephones because that is often how insurgents
pass orders to detonate a device.

"Everybody is pretty jumpy,"
explained Sgt. J.J. Chapa, a National Guardsman from Austin, Texas. "You're
constantly looking around. Your mind is shifting right and left everywhere you
go."

Despite the risks, most U.S. soldiers interviewed in recent weeks
said they believed strongly in the campaign to oust Saddam Hussein, whom they
describe as a brutal dictator who slaughtered thousands and hoarded riches while
impoverishing Iraq.

Many soldiers said they are less certain the U.S. can
bring lasting peace and democracy to a country they describe as riven by violence
and anarchy.

Others said their main concern is survival.

"I'm
not here for George Bush's foreign policy," Chapa said. "I'm here because
they sent me. We all have wives and children and we do what we have to do to get
back alive."